This invention relates to new and useful improvements in dolly constructions and is particularly concerned with a dolly arranged for connection to a towing vehicle for maneuvering trailers in yard areas or the like.
Devices have heretofore been proposed for maneuvering trailers in yard areas or the like in order that a road tractor can be in service while the trailer is being loaded or unloaded. Such dollies employ a fifth wheel for engagement with the king pin of a trailer and thus in operation are pivotally connected to a towing vehicle for maneuvering in the same manner as the usual tractor and trailer arrangement. In addition, the trailer to be maneuvered is in turn connected to the dolly, which vehicle assembly, in view of the double pivot connection, namely, one at the towing vehicle and one at the dolly, is very difficult to maneuver. Also, the principal portion of maneuvering in the yard is done by reverse movement of the towing vehicle, and the prior devices thus require a skilled operator. The prior dollies also have the disadvantage that they are difficult to attach to and detach from trailers since the trailer must be raised and lowered in order to be connected to or disconnected from said dollies. Inconvenience also exists in the prior dollies for attaching them to or detaching them from a towing vehicle.